Nissan Sentra CVT Transmissions...truth from a mechanic, and a question

I have a 2013 Sentra, and the transmission started going at 79,000 miles.  This happened last month (August, 2019). Since it was a certified used vehicle, I got a replacement transmission installed, at no cost (7 year, 100,000 mile powertrain warrentee.)

The replacement runs fine (so far) after putting 1,000 miles on it.

Today, I went to the dealership for an oil change.

When walking outside of the dealership, casually looking at cars on the lot, I saw 15 boxes. (see pictures) All 15 boxes said CVT on them. One box was a different size than the others. I don't know this, but I'm guessing the 14 smaller boxes were to replace transmissions for cars, and the other was for an SUV or a truck?

Plus, there was a used one sitting out there, as well.

So it looks like CVT transmission replacements are pretty common.

I spoke with a mechanic, and here's what he told me about Nissan CVT transmissions.

*  He recommends changing the transmission fluid (not just the gearbox, but flush and fill the entire system) every 30,000 miles. He says Nissan isn't completely clear about when to change the fluid, but from a mechanics perspective, 30,000 miles is the best gauge to go by.

*  He said the CVT transmissions for the smaller cars are build with a metal belt, vs a metal chain. These belts are the problem. When there is a lot of heat, (proper cooling is also an issue) and/or just the fact the belts are so thin, the transmission can start slipping. Eventually, these metal bands act like a rubber band that has been stretched to far, and too often. They lose their ability to hold, and slip. This causes stalling, jumping, shuttering, etc.

* He told me the larger cars, SUV's and trucks have metal CHAINS instead of BELTS. The chains have a much better history, and less of a failure rate. They are far less likely to stretch and slip.

* He told me, for the past year or year and a half, replacement transmissions for Nissan cars (like the Sentra) are being built with WIDER metal bands. This was improvement added to the replacement transmissions, to help them run better and last longer. So, if you got a replacement transmission recently, you probably got the better rebuild transmission, like I did.

* He also noted mechanics have complained to the creator of the transmission, asking that, instead of having the metal belt, a small metal chain be created in it's place, to improve performance and life. The response was that there isn't anything wrong with the build, so the creator of the transmission is leaving the type of build alone.

Now that all of these statements have been made, I do have a question.

Some of the boxes that I saw outside the dealership that were replacement CVT transmisions said Jatco (the company that Nissan uses to make their transmissions) but some said JME X. Is this an aftermarket transmission, or a division of Jatco?